DL021 From United States of America, joined May 2004, 11433 posts, RR: 81 Reply 1, posted (5 years 10 months 2 weeks 4 days 17 hours ago) and read 5917 times:
Very much so. I'm very glad that we chose such an excellent helicopter for this mission. I think it's the largest helo that can be conveniently carried by the C-5 and C-17, and it's the most modern three engined helo available. I like the extra security of the third engine when it comes to carrying our CINC.
I further have no real issue with the idea of buying some equipment from our allies....especially when a serious chunk of the work is being done here. It seems to be the best equipment for the job.....just like the EH-145/UH-72.
UH60FtRucker From , joined Dec 1969, posts, RR: Reply 5, posted (5 years 10 months 2 weeks 4 days 15 hours ago) and read 5859 times:
Quoting DeltaGuy (Reply 2): I'm not a helo nut by any stretch, but I thought NOTARS was the big trend nowadays? Or is that impractical on a helo that size?
Not really. It's an impressive technology, but only a few helicopters utilize it... and none of them very large helicopters.
A year ago when the Army was deciding which helicopter they wanted to fill the new LUH slot, one of the top runners was the MD Explorer... but the EH-145 won at the end of the day.
The NOTAR system offers some nice advantages - less noise (I was standing outside on the airfield with a MD500 hovering at 100ft over my head... and I was amazed at how quiet it was.) It also reduces the vibrations. Anyone who has flown in a helicopter -especially on a daily basis will tell you two things will wear your body down more than anything else: the noise of a helicopter, and the vibrations of a helicopter!
The conventional tail rotor is actually responsible for a vast amount of the noise a helicopter produces. Whereas it is linked to the main rotor system via a driveshaft... the tail rotor must spin much faster than the main rotors, thus producing more sound. Interestingly, in the UH-60 our tail rotor is mounted at a 20degree angle, which produces 2.5% of the total lift of the helicopter.
Anyway, the NOTAR system is also heavier, due to the large fan which forces low pressure air down the tail and out the "exhaust vents". It's also ineffective at high speeds, so conventional control surfaces help maintain forward stability during flight. And it's also less maneuverable as speed increases.
Like everything else - it's a trade off.
Quoting DeltaGuy (Reply 2): DeltaGuy (wouldn't know how to fly a helo if his life depended on it)
lol... well I don't want to talk myself up... but a monkey can fly an airplane. It takes a PILOT to fly a helicopter!
Anyway, this is going to make a fantastic Marine One. Say, do they let Army helicopter pilots fly these birds? Or do you have to be a marine aviator?
UH60FtRucker From , joined Dec 1969, posts, RR: Reply 13, posted (5 years 10 months 2 weeks 3 days 16 hours ago) and read 5543 times:
Quoting David L (Reply 8): Easier than I thought, then. I thought a helicopter pilot had to resemble an octopus with a chameleon's eyes.
lol... sometimes I wish I had as many arms as an octopus. Helicopters just simply require constant piloting and control.
Quoting Checksixx (Reply 11):
I understand what you meant, but for those who don't know, there are no MD500's with NOTAR...And yes, as UH60FtRucker stated, they are considerably more quiet.
You're right, it was the MDExplorer. Must have been a brain-fart.
Quoting BladeLWS (Reply 9): A shrouded rotor reduces noise alot for urban areas, but it's draw back is that it adds weight and needs a stronger boom to support it.
Quoting Checksixx (Reply 12): Actually as Eurocopter found out, the fenestron tail rotor system was MUCH louder. This is the main reason that they recently redesigned it with off-set blades in order to reduce the noise.
That's interesting, I wonder why that was? Was it just this particular helicopter? Because I know that in the case of the RAH-66, the tail rotor noise was lowered substantially by enclosing it in a shroud.
The shroud will typically direct the noise to the sides of the helicopter... and not down. Therefore, those standing below a helicopter will not hear as much noise. Also the shroud will help minimize the tail rotor vortices interacting with the main rotor vortices, creating less vibration, and thus more comfort for the passengers and crew. The shroud also minimizes the chance of you sticking your tail rotor into something - which surprisingly happens more often then some might think! Like I said - tail rotors cause a disproportionate amount of noise for their size - due to their faster rotation. And that noise is higher pitched, and very loud to the human ear. I HATE standing outside a UH-60 when the throttle is full forward - that tail rotor hurts the ears.
The problem is like BladeLWS said - it's heavy. However, the shroud offers BETTER aerodynamic performance by reducing certain vortex creations and interactions.
UH60FtRucker From , joined Dec 1969, posts, RR: Reply 16, posted (5 years 10 months 2 weeks 3 days 13 hours ago) and read 5488 times:
Quoting A342 (Reply 14): To get back to the article (FI also has one),
is the need for a new presidential helo so pressing that they can't wait to get the definitive (Increment 2) aircraft?
Quote: "The focus for Increment 1 is to deliver maximum capability within an aggressive schedule," notes Dewar. "While we test the aircraft and gear up for production, concurrent engineering will allow a seamless transition to Increment 2. We will deliver a mission-ready aircraft four years after contract award. The fully mission capable aircraft will be delivered two years after that."
TV-1 through TV-5 will be Increment 1 aircraft, and will be used to test the technology and additional features that will be found on the VH-71.
TV-6 will be the first Increment 2 aircraft, and will be used for aircraft performance evaluations, for which performance charts for the VH-71 will be based off of.
The eighteen Increment 2 production aircraft will come off a second assembly line in Amarillo, Texas. Full Yankee White security protocols will be in effect at this factory.
DL021 From United States of America, joined May 2004, 11433 posts, RR: 81 Reply 17, posted (5 years 10 months 2 weeks 3 days 13 hours ago) and read 5487 times:
Quoting Checksixx (Reply 10): Not at all...I meant built which means assembled smarty pants.
Well....to be fair many people may be of the opinion that "built" means parts forged and built here as well as assembled into a large constellation of parts that will all move in the same direction at the same speed....if we're all very lucky!
The aircraft assembly issue is one that is touchy....are the AV-8B's built here or assembled here? The engines and parts kits came from elsewhere, so I guess it's opinion or interpretation.
AutoThrust From Switzerland, joined Jun 2006, 1480 posts, RR: 8 Reply 18, posted (5 years 10 months 2 weeks 3 days 12 hours ago) and read 5461 times:
I wonder why they didnt choose the much more modern NH-90, was it to small? To less range?
# Length: 16.13 m (52 ft 11 in)
# Rotor diameter: 16.30 m (53 ft 5¾ in)
# Height: 5.23 m (17 ft 2 in)
# Empty weight: 5,400 kg (11,900 lb)
# Max takeoff weight: 10,600 kg (23,370 lb)
# Range: 800 km (TTH); 1,000 km
# Length: 74 ft 10 in (22.81 m)
# Rotor diameter: 61 ft 0 in (18.59 m)
# Height: 21 ft 10 in (6.65 m)
# Empty weight: 23,150 lb (10,500 kg)
# Useful load: 12,000 lb (5,443 kg)
# Max takeoff weight: 32,188 lb (14,600 kg)
# Range: 750 nm (863 mi, 1389 km)
DL021 From United States of America, joined May 2004, 11433 posts, RR: 81 Reply 19, posted (5 years 10 months 2 weeks 3 days 7 hours ago) and read 5396 times:
Quoting AutoThrust (Reply 18): I wonder why they didnt choose the much more modern NH-90, was it to small? To less range?
Well....the NH90 is not really "much more modern". It has half the payload capacity, one less engine, alot less room, and would not have beaten the Sikorsky S-92 offering, much less the superior capability Merlin-type.
Size definitely played a role, on top of the power and other issues.
Quoting FI: AgustaWestland has flown the first test aircraft built specifically for the Lockheed Martin VH-71 US presidential helicopter programme. (...)
Under Increment 1 of the programme, three additional test aircraft will fly by early 2008 and five pilot-production VH-71s will be delivered by October 2009 to meet the urgent requirement for a new presidential helicopter.
An improved version of the helicopter with increased performance will be developed for Increment 2. This will have uprated engines, a new transmission, longer rotor blades and extended tailboom to give the helicopter longer range and a command and control capability while in flight.
Original plans called for 18 new Increment 2 helicopters, plus upgrades to the Increment 1 machines, but because of the extensive changes the VH-71 team has recommended production of 23 new Increment 2 helicopters.(...)
VH-71 prime contractor Lockheed Martin is already using an EH101, designated TV-1, for initial testing in the USA, including landings on the White House lawn.
AutoThrust From Switzerland, joined Jun 2006, 1480 posts, RR: 8 Reply 22, posted (5 years 10 months 2 weeks 2 days 22 hours ago) and read 5329 times:
Quoting DL021 (Reply 19): Well....the NH90 is not really "much more modern"
Sorry thats not true, the NH-90 is much more modern; it has a fully 4x redundant digital fly by wire which the helicopter can fly automatic and hover without manual input. The Fuselage is mainly CFRP with Fibre Reinforced Plastic which provides much less corrosion with low Radar signature.
Besides it has several computers for Navigation,Communication,Monitoring,Surveillance,Diagnosis,etc..
Avionics system based on a dual MIL-STD-1553B digital databus. Further upgrades will provide the NH-90 with care free handling features. I couldnt find much more information.
The EH-101 has a electromechanical BAE systems flyby wire and a modular aluminium-lithium alloy fuselage.The EH101 is equipped with helicopter management, avionics and mission systems linked by two 1553B multiplex databuses.
Quoting DL021 (Reply 19): Size definitely played a role, on top of the power and other issues.
Agreed, the EH-101 is sure a great helicopter and will server well as presidential chopper.
DL021 From United States of America, joined May 2004, 11433 posts, RR: 81 Reply 23, posted (5 years 10 months 2 weeks 2 days 17 hours ago) and read 5256 times:
AUto...well...ok...it looks to me like they're both served by the same computers and safety systems...but you are correct in that the carbonfibre body on the NH is more advanced than the al-li loy on the Merlin...
I'd have to say though that they are the same generation of airplane and relatively equal in their electronics and engine tech.
But we do agree that the VH-71 will serve the mission very well.